如何用VSCode和Clangd与Clang-Format插件高效阅读Linux内核源码及写驱动

一、如何高效阅读Linux源码：基于clangd

uboot/busybox等都可以用这种方式，理论上说所有基于Make和Cmake的源码工程都可以用这套方案

阅读Linux源码最大问题在于调用链太复杂，一个函数或变量引用太多，source insight和cscope等基于文本检索类似的工具，分析都不够精确，clangd是在编译过程分析调用关系，结果要准确地多，使用效果极佳。下面截取几个图展示下clangd的强大之处

Kconfig和Makefile中定义的配置项宏如果为0，Clangd检索完VScode会把没走到的分支自动注释掉，大大降低我们分析源码时走错分支的可能性

右键ShowCallHierarchy调用栈分析一步到位

精准强大的代码补全

在写驱动时，对内核方法和对象的提示非常全和准确

创建索引非常快，5.10.99的内核全量创建索引只需约2分钟，busybox和uboot的源码十几秒就好了

创建索引非常快，5.10.99的内核全量创建索引只需约2分钟，busybox和uboot的源码十几秒就好了

搭建教程参考

https://blog.csdn.net/thisway_diy/article/details/127426986

二、写驱动时如何自动格式化并(最好和Linux内核源码一个风格！！！）

1.VScode安装Clang-Format插件

左侧插件市场搜索直接安装即可

2.给系统安装clang-format

以Ubuntu为例，其他系统类似

sudo apt-get install clang-format

3.从Linux源码根目录把.clang-format文件拷贝到自己的项目目录

5.10.99亲测官方源码就有.clang-format文件，不过4.x版本没有，应该是5.x引进的，方便内核开发人员统一编码风格的

防止的Linux内核源码版本低，这里拷贝一份过来，大家可以在自己的工程目录手动创建.clang-format文件，并把下面的内容复制进去

# SPDX-License-Identifier: GPL-2.0

#

# clang-format configuration file. Intended for clang-format >= 4.

#

# For more information, see:

#

# Documentation/process/clang-format.rst

# https://clang.llvm.org/docs/ClangFormat.html

# https://clang.llvm.org/docs/ClangFormatStyleOptions.html

#

---

AccessModifierOffset: -4

AlignAfterOpenBracket: Align

AlignConsecutiveAssignments: false

AlignConsecutiveDeclarations: false

#AlignEscapedNewlines: Left # Unknown to clang-format-4.0

AlignOperands: true

AlignTrailingComments: false

AllowAllParametersOfDeclarationOnNextLine: false

AllowShortBlocksOnASingleLine: false

AllowShortCaseLabelsOnASingleLine: false

AllowShortFunctionsOnASingleLine: None

AllowShortIfStatementsOnASingleLine: false

AllowShortLoopsOnASingleLine: false

AlwaysBreakAfterDefinitionReturnType: None

AlwaysBreakAfterReturnType: None

AlwaysBreakBeforeMultilineStrings: false

AlwaysBreakTemplateDeclarations: false

BinPackArguments: true

BinPackParameters: true

BraceWrapping:

AfterClass: false

AfterControlStatement: false

AfterEnum: false

AfterFunction: true

AfterNamespace: true

AfterObjCDeclaration: false

AfterStruct: false

AfterUnion: false

#AfterExternBlock: false # Unknown to clang-format-5.0

BeforeCatch: false

BeforeElse: false

IndentBraces: false

#SplitEmptyFunction: true # Unknown to clang-format-4.0

#SplitEmptyRecord: true # Unknown to clang-format-4.0

#SplitEmptyNamespace: true # Unknown to clang-format-4.0

BreakBeforeBinaryOperators: None

BreakBeforeBraces: Custom

#BreakBeforeInheritanceComma: false # Unknown to clang-format-4.0

BreakBeforeTernaryOperators: false

BreakConstructorInitializersBeforeComma: false

#BreakConstructorInitializers: BeforeComma # Unknown to clang-format-4.0

BreakAfterJavaFieldAnnotations: false

BreakStringLiterals: false

ColumnLimit: 80

CommentPragmas: '^ IWYU pragma:'

#CompactNamespaces: false # Unknown to clang-format-4.0

ConstructorInitializerAllOnOneLineOrOnePerLine: false

ConstructorInitializerIndentWidth: 8

ContinuationIndentWidth: 8

Cpp11BracedListStyle: false

DerivePointerAlignment: false

DisableFormat: false

ExperimentalAutoDetectBinPacking: false

#FixNamespaceComments: false # Unknown to clang-format-4.0

# Taken from:

# git grep -h '^#define [^[:space:]]*for_each[^[:space:]]*(' include/ \

# | sed "s,^#define \([^[:space:]]*for_each[^[:space:]]*\)(.*$, - '\1'," \

# | sort | uniq

ForEachMacros:

- 'apei_estatus_for_each_section'

- 'ata_for_each_dev'

- 'ata_for_each_link'

- '__ata_qc_for_each'

- 'ata_qc_for_each'

- 'ata_qc_for_each_raw'

- 'ata_qc_for_each_with_internal'

- 'ax25_for_each'

- 'ax25_uid_for_each'

- '__bio_for_each_bvec'

- 'bio_for_each_bvec'

- 'bio_for_each_bvec_all'

- 'bio_for_each_integrity_vec'

- '__bio_for_each_segment'

- 'bio_for_each_segment'

- 'bio_for_each_segment_all'

- 'bio_list_for_each'

- 'bip_for_each_vec'

- 'bitmap_for_each_clear_region'

- 'bitmap_for_each_set_region'

- 'blkg_for_each_descendant_post'

- 'blkg_for_each_descendant_pre'

- 'blk_queue_for_each_rl'

- 'bond_for_each_slave'

- 'bond_for_each_slave_rcu'

- 'bpf_for_each_spilled_reg'

- 'btree_for_each_safe128'

- 'btree_for_each_safe32'

- 'btree_for_each_safe64'

- 'btree_for_each_safel'

- 'card_for_each_dev'

- 'cgroup_taskset_for_each'

- 'cgroup_taskset_for_each_leader'

- 'cpufreq_for_each_entry'

- 'cpufreq_for_each_entry_idx'

- 'cpufreq_for_each_valid_entry'

- 'cpufreq_for_each_valid_entry_idx'

- 'css_for_each_child'

- 'css_for_each_descendant_post'

- 'css_for_each_descendant_pre'

- 'device_for_each_child_node'

- 'dma_fence_chain_for_each'

- 'do_for_each_ftrace_op'

- 'drm_atomic_crtc_for_each_plane'

- 'drm_atomic_crtc_state_for_each_plane'

- 'drm_atomic_crtc_state_for_each_plane_state'

- 'drm_atomic_for_each_plane_damage'

- 'drm_client_for_each_connector_iter'

- 'drm_client_for_each_modeset'

- 'drm_connector_for_each_possible_encoder'

- 'drm_for_each_bridge_in_chain'

- 'drm_for_each_connector_iter'

- 'drm_for_each_crtc'

- 'drm_for_each_encoder'

- 'drm_for_each_encoder_mask'

- 'drm_for_each_fb'

- 'drm_for_each_legacy_plane'

- 'drm_for_each_plane'

- 'drm_for_each_plane_mask'

- 'drm_for_each_privobj'

- 'drm_mm_for_each_hole'

- 'drm_mm_for_each_node'

- 'drm_mm_for_each_node_in_range'

- 'drm_mm_for_each_node_safe'

- 'flow_action_for_each'

- 'for_each_active_dev_scope'

- 'for_each_active_drhd_unit'

- 'for_each_active_iommu'

- 'for_each_aggr_pgid'

- 'for_each_available_child_of_node'

- 'for_each_bio'

- 'for_each_board_func_rsrc'

- 'for_each_bvec'

- 'for_each_card_auxs'

- 'for_each_card_auxs_safe'

- 'for_each_card_components'

- 'for_each_card_dapms'

- 'for_each_card_pre_auxs'

- 'for_each_card_prelinks'

- 'for_each_card_rtds'

- 'for_each_card_rtds_safe'

- 'for_each_card_widgets'

- 'for_each_card_widgets_safe'

- 'for_each_cgroup_storage_type'

- 'for_each_child_of_node'

- 'for_each_clear_bit'

- 'for_each_clear_bit_from'

- 'for_each_cmsghdr'

- 'for_each_compatible_node'

- 'for_each_component_dais'

- 'for_each_component_dais_safe'

- 'for_each_comp_order'

- 'for_each_console'

- 'for_each_cpu'

- 'for_each_cpu_and'

- 'for_each_cpu_not'

- 'for_each_cpu_wrap'

- 'for_each_dapm_widgets'

- 'for_each_dev_addr'

- 'for_each_dev_scope'

- 'for_each_displayid_db'

- 'for_each_dma_cap_mask'

- 'for_each_dpcm_be'

- 'for_each_dpcm_be_rollback'

- 'for_each_dpcm_be_safe'

- 'for_each_dpcm_fe'

- 'for_each_drhd_unit'

- 'for_each_dss_dev'

- 'for_each_efi_memory_desc'

- 'for_each_efi_memory_desc_in_map'

- 'for_each_element'

- 'for_each_element_extid'

- 'for_each_element_id'

- 'for_each_endpoint_of_node'

- 'for_each_evictable_lru'

- 'for_each_fib6_node_rt_rcu'

- 'for_each_fib6_walker_rt'

- 'for_each_free_mem_pfn_range_in_zone'

- 'for_each_free_mem_pfn_range_in_zone_from'

- 'for_each_free_mem_range'

- 'for_each_free_mem_range_reverse'

- 'for_each_func_rsrc'

- 'for_each_hstate'

- 'for_each_if'

- 'for_each_iommu'

- 'for_each_ip_tunnel_rcu'

- 'for_each_irq_nr'

- 'for_each_link_codecs'

- 'for_each_link_cpus'

- 'for_each_link_platforms'

- 'for_each_lru'

- 'for_each_matching_node'

- 'for_each_matching_node_and_match'

- 'for_each_member'

- 'for_each_mem_region'

- 'for_each_memblock_type'

- 'for_each_memcg_cache_index'

- 'for_each_mem_pfn_range'

- '__for_each_mem_range'

- 'for_each_mem_range'

- '__for_each_mem_range_rev'

- 'for_each_mem_range_rev'

- 'for_each_migratetype_order'

- 'for_each_msi_entry'

- 'for_each_msi_entry_safe'

- 'for_each_net'

- 'for_each_net_continue_reverse'

- 'for_each_netdev'

- 'for_each_netdev_continue'

- 'for_each_netdev_continue_rcu'

- 'for_each_netdev_continue_reverse'

- 'for_each_netdev_feature'

- 'for_each_netdev_in_bond_rcu'

- 'for_each_netdev_rcu'

- 'for_each_netdev_reverse'

- 'for_each_netdev_safe'

- 'for_each_net_rcu'

- 'for_each_new_connector_in_state'

- 'for_each_new_crtc_in_state'

- 'for_each_new_mst_mgr_in_state'

- 'for_each_new_plane_in_state'

- 'for_each_new_private_obj_in_state'

- 'for_each_node'

- 'for_each_node_by_name'

- 'for_each_node_by_type'

- 'for_each_node_mask'

- 'for_each_node_state'

- 'for_each_node_with_cpus'

- 'for_each_node_with_property'

- 'for_each_nonreserved_multicast_dest_pgid'

- 'for_each_of_allnodes'

- 'for_each_of_allnodes_from'

- 'for_each_of_cpu_node'

- 'for_each_of_pci_range'

- 'for_each_old_connector_in_state'

- 'for_each_old_crtc_in_state'

- 'for_each_old_mst_mgr_in_state'

- 'for_each_oldnew_connector_in_state'

- 'for_each_oldnew_crtc_in_state'

- 'for_each_oldnew_mst_mgr_in_state'

- 'for_each_oldnew_plane_in_state'

- 'for_each_oldnew_plane_in_state_reverse'

- 'for_each_oldnew_private_obj_in_state'

- 'for_each_old_plane_in_state'

- 'for_each_old_private_obj_in_state'

- 'for_each_online_cpu'

- 'for_each_online_node'

- 'for_each_online_pgdat'

- 'for_each_pci_bridge'

- 'for_each_pci_dev'

- 'for_each_pci_msi_entry'

- 'for_each_pcm_streams'

- 'for_each_physmem_range'

- 'for_each_populated_zone'

- 'for_each_possible_cpu'

- 'for_each_present_cpu'

- 'for_each_prime_number'

- 'for_each_prime_number_from'

- 'for_each_process'

- 'for_each_process_thread'

- 'for_each_property_of_node'

- 'for_each_registered_fb'

- 'for_each_requested_gpio'

- 'for_each_requested_gpio_in_range'

- 'for_each_reserved_mem_range'

- 'for_each_reserved_mem_region'

- 'for_each_rtd_codec_dais'

- 'for_each_rtd_codec_dais_rollback'

- 'for_each_rtd_components'

- 'for_each_rtd_cpu_dais'

- 'for_each_rtd_cpu_dais_rollback'

- 'for_each_rtd_dais'

- 'for_each_set_bit'

- 'for_each_set_bit_from'

- 'for_each_set_clump8'

- 'for_each_sg'

- 'for_each_sg_dma_page'

- 'for_each_sg_page'

- 'for_each_sgtable_dma_page'

- 'for_each_sgtable_dma_sg'

- 'for_each_sgtable_page'

- 'for_each_sgtable_sg'

- 'for_each_sibling_event'

- 'for_each_subelement'

- 'for_each_subelement_extid'

- 'for_each_subelement_id'

- '__for_each_thread'

- 'for_each_thread'

- 'for_each_unicast_dest_pgid'

- 'for_each_wakeup_source'

- 'for_each_zone'

- 'for_each_zone_zonelist'

- 'for_each_zone_zonelist_nodemask'

- 'fwnode_for_each_available_child_node'

- 'fwnode_for_each_child_node'

- 'fwnode_graph_for_each_endpoint'

- 'gadget_for_each_ep'

- 'genradix_for_each'

- 'genradix_for_each_from'

- 'hash_for_each'

- 'hash_for_each_possible'

- 'hash_for_each_possible_rcu'

- 'hash_for_each_possible_rcu_notrace'

- 'hash_for_each_possible_safe'

- 'hash_for_each_rcu'

- 'hash_for_each_safe'

- 'hctx_for_each_ctx'

- 'hlist_bl_for_each_entry'

- 'hlist_bl_for_each_entry_rcu'

- 'hlist_bl_for_each_entry_safe'

- 'hlist_for_each'

- 'hlist_for_each_entry'

- 'hlist_for_each_entry_continue'

- 'hlist_for_each_entry_continue_rcu'

- 'hlist_for_each_entry_continue_rcu_bh'

- 'hlist_for_each_entry_from'

- 'hlist_for_each_entry_from_rcu'

- 'hlist_for_each_entry_rcu'

- 'hlist_for_each_entry_rcu_bh'

- 'hlist_for_each_entry_rcu_notrace'

- 'hlist_for_each_entry_safe'

- '__hlist_for_each_rcu'

- 'hlist_for_each_safe'

- 'hlist_nulls_for_each_entry'

- 'hlist_nulls_for_each_entry_from'

- 'hlist_nulls_for_each_entry_rcu'

- 'hlist_nulls_for_each_entry_safe'

- 'i3c_bus_for_each_i2cdev'

- 'i3c_bus_for_each_i3cdev'

- 'ide_host_for_each_port'

- 'ide_port_for_each_dev'

- 'ide_port_for_each_present_dev'

- 'idr_for_each_entry'

- 'idr_for_each_entry_continue'

- 'idr_for_each_entry_continue_ul'

- 'idr_for_each_entry_ul'

- 'in_dev_for_each_ifa_rcu'

- 'in_dev_for_each_ifa_rtnl'

- 'inet_bind_bucket_for_each'

- 'inet_lhash2_for_each_icsk_rcu'

- 'key_for_each'

- 'key_for_each_safe'

- 'klp_for_each_func'

- 'klp_for_each_func_safe'

- 'klp_for_each_func_static'

- 'klp_for_each_object'

- 'klp_for_each_object_safe'

- 'klp_for_each_object_static'

- 'kunit_suite_for_each_test_case'

- 'kvm_for_each_memslot'

- 'kvm_for_each_vcpu'

- 'list_for_each'

- 'list_for_each_codec'

- 'list_for_each_codec_safe'

- 'list_for_each_continue'

- 'list_for_each_entry'

- 'list_for_each_entry_continue'

- 'list_for_each_entry_continue_rcu'

- 'list_for_each_entry_continue_reverse'

- 'list_for_each_entry_from'

- 'list_for_each_entry_from_rcu'

- 'list_for_each_entry_from_reverse'

- 'list_for_each_entry_lockless'

- 'list_for_each_entry_rcu'

- 'list_for_each_entry_reverse'

- 'list_for_each_entry_safe'

- 'list_for_each_entry_safe_continue'

- 'list_for_each_entry_safe_from'

- 'list_for_each_entry_safe_reverse'

- 'list_for_each_prev'

- 'list_for_each_prev_safe'

- 'list_for_each_safe'

- 'llist_for_each'

- 'llist_for_each_entry'

- 'llist_for_each_entry_safe'

- 'llist_for_each_safe'

- 'mci_for_each_dimm'

- 'media_device_for_each_entity'

- 'media_device_for_each_intf'

- 'media_device_for_each_link'

- 'media_device_for_each_pad'

- 'nanddev_io_for_each_page'

- 'netdev_for_each_lower_dev'

- 'netdev_for_each_lower_private'

- 'netdev_for_each_lower_private_rcu'

- 'netdev_for_each_mc_addr'

- 'netdev_for_each_uc_addr'

- 'netdev_for_each_upper_dev_rcu'

- 'netdev_hw_addr_list_for_each'

- 'nft_rule_for_each_expr'

- 'nla_for_each_attr'

- 'nla_for_each_nested'

- 'nlmsg_for_each_attr'

- 'nlmsg_for_each_msg'

- 'nr_neigh_for_each'

- 'nr_neigh_for_each_safe'

- 'nr_node_for_each'

- 'nr_node_for_each_safe'

- 'of_for_each_phandle'

- 'of_property_for_each_string'

- 'of_property_for_each_u32'

- 'pci_bus_for_each_resource'

- 'pcm_for_each_format'

- 'ping_portaddr_for_each_entry'

- 'plist_for_each'

- 'plist_for_each_continue'

- 'plist_for_each_entry'

- 'plist_for_each_entry_continue'

- 'plist_for_each_entry_safe'

- 'plist_for_each_safe'

- 'pnp_for_each_card'

- 'pnp_for_each_dev'

- 'protocol_for_each_card'

- 'protocol_for_each_dev'

- 'queue_for_each_hw_ctx'

- 'radix_tree_for_each_slot'

- 'radix_tree_for_each_tagged'

- 'rbtree_postorder_for_each_entry_safe'

- 'rdma_for_each_block'

- 'rdma_for_each_port'

- 'rdma_umem_for_each_dma_block'

- 'resource_list_for_each_entry'

- 'resource_list_for_each_entry_safe'

- 'rhl_for_each_entry_rcu'

- 'rhl_for_each_rcu'

- 'rht_for_each'

- 'rht_for_each_entry'

- 'rht_for_each_entry_from'

- 'rht_for_each_entry_rcu'

- 'rht_for_each_entry_rcu_from'

- 'rht_for_each_entry_safe'

- 'rht_for_each_from'

- 'rht_for_each_rcu'

- 'rht_for_each_rcu_from'

- '__rq_for_each_bio'

- 'rq_for_each_bvec'

- 'rq_for_each_segment'

- 'scsi_for_each_prot_sg'

- 'scsi_for_each_sg'

- 'sctp_for_each_hentry'

- 'sctp_skb_for_each'

- 'shdma_for_each_chan'

- '__shost_for_each_device'

- 'shost_for_each_device'

- 'sk_for_each'

- 'sk_for_each_bound'

- 'sk_for_each_entry_offset_rcu'

- 'sk_for_each_from'

- 'sk_for_each_rcu'

- 'sk_for_each_safe'

- 'sk_nulls_for_each'

- 'sk_nulls_for_each_from'

- 'sk_nulls_for_each_rcu'

- 'snd_array_for_each'

- 'snd_pcm_group_for_each_entry'

- 'snd_soc_dapm_widget_for_each_path'

- 'snd_soc_dapm_widget_for_each_path_safe'

- 'snd_soc_dapm_widget_for_each_sink_path'

- 'snd_soc_dapm_widget_for_each_source_path'

- 'tb_property_for_each'

- 'tcf_exts_for_each_action'

- 'udp_portaddr_for_each_entry'

- 'udp_portaddr_for_each_entry_rcu'

- 'usb_hub_for_each_child'

- 'v4l2_device_for_each_subdev'

- 'v4l2_m2m_for_each_dst_buf'

- 'v4l2_m2m_for_each_dst_buf_safe'

- 'v4l2_m2m_for_each_src_buf'

- 'v4l2_m2m_for_each_src_buf_safe'

- 'virtio_device_for_each_vq'

- 'while_for_each_ftrace_op'

- 'xa_for_each'

- 'xa_for_each_marked'

- 'xa_for_each_range'

- 'xa_for_each_start'

- 'xas_for_each'

- 'xas_for_each_conflict'

- 'xas_for_each_marked'

- 'xbc_array_for_each_value'

- 'xbc_for_each_key_value'

- 'xbc_node_for_each_array_value'

- 'xbc_node_for_each_child'

- 'xbc_node_for_each_key_value'

- 'zorro_for_each_dev'

#IncludeBlocks: Preserve # Unknown to clang-format-5.0

IncludeCategories:

- Regex: '.*'

Priority: 1

IncludeIsMainRegex: '(Test)?$'

IndentCaseLabels: false

#IndentPPDirectives: None # Unknown to clang-format-5.0

IndentWidth: 8

IndentWrappedFunctionNames: false

JavaScriptQuotes: Leave

JavaScriptWrapImports: true

KeepEmptyLinesAtTheStartOfBlocks: false

MacroBlockBegin: ''

MacroBlockEnd: ''

MaxEmptyLinesToKeep: 1

NamespaceIndentation: None

#ObjCBinPackProtocolList: Auto # Unknown to clang-format-5.0

ObjCBlockIndentWidth: 8

ObjCSpaceAfterProperty: true

ObjCSpaceBeforeProtocolList: true

# Taken from git's rules

#PenaltyBreakAssignment: 10 # Unknown to clang-format-4.0

PenaltyBreakBeforeFirstCallParameter: 30

PenaltyBreakComment: 10

PenaltyBreakFirstLessLess: 0

PenaltyBreakString: 10

PenaltyExcessCharacter: 100

PenaltyReturnTypeOnItsOwnLine: 60

PointerAlignment: Right

ReflowComments: false

SortIncludes: false

#SortUsingDeclarations: false # Unknown to clang-format-4.0

SpaceAfterCStyleCast: false

SpaceAfterTemplateKeyword: true

SpaceBeforeAssignmentOperators: true

#SpaceBeforeCtorInitializerColon: true # Unknown to clang-format-5.0

#SpaceBeforeInheritanceColon: true # Unknown to clang-format-5.0

SpaceBeforeParens: ControlStatements

#SpaceBeforeRangeBasedForLoopColon: true # Unknown to clang-format-5.0

SpaceInEmptyParentheses: false

SpacesBeforeTrailingComments: 1

SpacesInAngles: false

SpacesInContainerLiterals: false

SpacesInCStyleCastParentheses: false

SpacesInParentheses: false

SpacesInSquareBrackets: false

Standard: Cpp03

TabWidth: 8

UseTab: Always

...

4.设置clang-format为默认格式化插件

操作如下

5.设置格式化时机为format on save

6.打开自己的代码文件，随便修改点，按Ctrl+S保存，代码即可自动格式化，而且和内核风格完全一样

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